Mainsail feeder for sailboat



FIG. 1 is a perspective view of a mainsail feeder for sailboat, showing my new design;

FIG. 2 is a top plan view thereof, the bottom view being identical thereto;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a side elevational view thereof;

FIG. 5 is a front elevational view thereof. 

The ornamental design for a mainsail feeder for sailboat, as shown and described. 